Process of and apparatus for baking carbonaceous materials



Nov. 24, 1931. w. E. TRENT PROCESS OF AND APPARATUS FOR BAKING CARBONACEOUS MATEBLS Filed Jan- 18, 1928 8 Sheetsnheet l ,awww/wg WALTER A Nov. .24, 1931. w. E. TRENT 1,833,801

PROCESS OF AND APPARATUS FOR BAKING CARBONACEOUS MATERIALS Filed Jan. 18, 1928 8 Sheets-Sheet 2 JNVENTR. WALT-ER E TRENT A TToRNEYy" l. l I l W. E. TRENT NHV. 221, 1931.

PROCESS 0F AND APPARATUS FOR BAKING CARBONACEOUS MATERIALS Filed Jan. 18, 1928 8 Sheets-Sheet 3 E vm.

` ATTORNEYS.

W. E. TRENT l Nov. 24, 1931.

PROCESS OF AND APPARATUS FOR BAKING CARBONACEOUS MATERIALS Filed Jan. 18, 1928 8 Sheets-Sheet 4 IENTORFI' WALTER EA.TRENT.

d ATToRNEYsr. ,Y I

w-. E. TRENT 1,8335801 PROCESS v0F' AND APPARATUS FOR BAKING CARBONACEOUS MATERIALS Nov. 24, 1931.

a sheets-shed 5 Filed Jan. 18, 1928 INVENTORY. WALTER E ,TR ENT A TTORNEYS.

NOV. 24, 1931. wl E, TREN-r 1,833,801

PROCESS OF AND APPARATUS FOR BAKING CARBQNACEOUS MATERIALS W. E. TRENT.

Nov. 24, 1931.

PROCESS OF AND APPARATUS FOR BAKING CARBONACEOUS MATERIALS Filed Jan. 18, 1928 8 Sheets-Sheet 7 SE x@ @u .m E Q\ G N w il *ISL/ Q.

INVENTOR. WALTER-E .TR ENT A TTORNEYS.

w. E. .'rRr-:N'r 1,833,801

PROCESS OF AND APPARATUS FOR BAKING CARBONACEOUS MATERIALS Nov. 24, 1931.

Filed Jan- 18, 1928 8 Sheets-Sheet 8 O IG.. IGI Gl i@ @i '@I 9 n e v a www v Q`.\ W QMT* M \\N l o o o o o o o e o V .H H H H INVENTOR. WA`LTER.E.TRENT BY ATTORNEY 50 advantageously andthe Patented Nov. 24, 1931 vUNITI-:n STATESIPATENT OFFICE WALTER E. TRmTT, Ol' NEW YORK, N'. Y., ASSIGNOB TO THE TBENT EXB'OCESS CORPORA- TION, A CORPORATION OF DELAWARE PROCESS OF AND APPARATUS FOR IBAXING CARBONACEOUS MATERIALS Application led January 18, 1928. Serial No. 247,875.

My invention relates to an apparatus for heating materials and particularly to an apparatus designed to bake amalgam briquettes in two stages according to the method disclosed in my co-pending application Serial .1,0 teachings of my former Patents Nos. 1,46%#

164 and 1,464,165. My invention, however, is adapted in its broader aspects to heating other materials and contains certain features of charging and 'discharging and heat conservation, etc. which may be applied in other combinations. While my invention preferably comprises an oven having a plurality of heating chambers adapted to successively bake charges of material for substantially uniform times, itis apparent that certain features of my invention, particularly the heat conservation features and certain features of my loading apparatus, may be applied to an individual oven.

The 'heat conservation features of my invention includev means for controlling the temperature of the heating gases by returning and mixing therewith a predetermined portion of the products' of combustion; a condenser intermittently connectible to saidl oven and means to return the non-condensed volatiles and gases from said condenser as fuel to the fire box instead of exhausting them into the air; means to admit air to said oven and to steps applied to the fuel contained vin each oven successively.

Further objects of my invention relate to the specific construction of my multiple chamber baking oven. I provide a battery of normally closed horizontal baking ovens vertically disposed' one above the other, each having one or more fuel containers removable from one end thereof for charging and discharging purposes. The ovens are vertically spaced from each other to provide horizontal transverse passageways for uniform application of heat thereto, and I preferably provide bal'llesor other means in said horizontal passageways to produce a turbulent ow of heating gases therethrough. 1

I further provide a multiple chamber baking oven which merely consists of a plurality of castings and which is thus very easy to construct and assemble. Each casting is so shaped as'to define an enclosed transverse passageway preferably having baffles therein, and Vhas legs substantially the length of the casting depending from each side thereof, and other legs extending upwardly from each side. The respective pairs of legs'are provided with means at their outer extremities causing such castings, when assembled with other similar castings in forming a multiple chamberoven, to be held in fixed relation to one another. Such means may, for example, consist of longitudinal grooves or slots in the outer edge portions of certain legs and beveled portions on other legs sor that when the /leadvthe air and the volatiles, evolved durcastings are assembled the beveled portions ing the second stage of the heat treatment,

from the oven to the fire box, saidmeans' being connectible to said oven alternately with the condenser, to serve as an additional 40 source of fuel andair for com ,ustion during same.

the second stage; and means to pass said air @prior to its entry to said/'oven in counter-current heat interchangey Withthe waste products of combustion of the fuel to preheat the In my preferred apparatus, I, have embodied all these features into a device includi ,1f/a plurality, of heating chambers so a/rried that the chargingfand dischargin features of my invention may be employ respective lbaking of the legson one casting will seat in the grooves or slots on the legs of an adjacent casting. By means of these castings it is a relatively simple matter to build u a bakin apparatus comprising'a battery of orizonta baking ovens vertically disposed one above the Other, and a plurality of enclosed transverse passageways extending underneatheach oven to impartindirect heat thereto. I preferably construct these castings withopenings adjacent each side thereof to permit heating gases to be introduced 0n-one side and caused to travel in zigzag paths around the baill'es provided therein to better impart heat `to ovens adjacent thereto. r

Further novel features of my invention re- .late to the method of loading and unloading the fuel containers, particularly .to the novel featureof changing the continuous feed from the extruding or briquetting machine, or the rounding-off machine if this is also emplo ed, to an intermittent feed to each oven to oad each respective oven with a substantially equal fuel charge. v

In the method of lcontinuously making amalgam as more particularly described in my co-pending a plication Serial No. 204,069, filed July 7 192%, i amalgam comes through an extruding machine, vand also if desired through my improved rounding-off machine. Due to the details of that process it functions mosteconomically continuously, but if the baking operation is to be carried out with optimum conditions of safety, oil recoveryand desired quality in the finished bri uette according to the teachirgs of my app ication Serial No. 234,261, file Nov. 18, 1927,/hereinbefore referred to, it is essential ,Y that the two stages of baking must be completely separated. Hence it is necessary to'l rovide means to change this continuous feed into an intermittent feed for each oven to 'loaduniform charges of fuel in each oven. To change this continuous feed from the eX- truding and rounding-off machines to a suitable intermittent feed to the ovens, I preferably provide an endless conveyor which is adaptedto be so operated and to be so moved relative to the extruding and rounding-oft' machines on the one. hand and to a position adjacent the charging and discharging openings of theovens on theother that the fuel chargesare continuously received on to the the extruding and roundingconveyor from off machines'and discharged therefrom intermittentlytocontainers being introduced into the ovens, I successively remove the fuel container vor containers from each individual u oven to a position underneath the conveyor, after subjecting the material inthe respective fuelcontainers to a two-stage heat treatment, dischargethe fuel charges carried by the con? veyor thereinto, and return the fuel containers to their respective ovens at such substantially uniform periods of time that each f oven will receive a substantially equal fuel charge from-the conveyor, and I coincidently dump the contents of eachfuel container` while attainingvits position underneath the conveyor-to recei ve a green fuel charge. The principles of loading and unloading the 44fuel container from the conveyor may be employed` if desired, on an individua-l oven but are particularlyadapted to successively load a ybattery of vertically-disposed ovens, and I therefore preferably mount fuel container supports or guideways and a discharging conveyory or other heated fuel receptacle on an 4elevator movable to positions underneath the a' continuous'feed of raw' from the `amalgam plant j 'loading Aand unloading breakage from a long fall. Further features of my invention relate to the mea-ns I preferably provide to attain a uniform charge of ,fuel on eachlo'ading conveyor.

As stated, my invention particularly relates to the heat treatment of amalgam briquettes.

I have found in ractice that if the amalgam briquettes are al owed to remain cylindrical the sharp edges thereof are liable to be broken off in use, thereby causing the briquettes to dust, for unlessthe heattreatment is very carefully regulated preferably in accordance .with the teachings of my patent application Serial No. 234,261 the inside portions of the briquettes are apt not `to be as hard as the outside portions and I havefound that I can produce briquettes much less liable to break or dust in use if I round off the edges of the briquettes prior to the baking treatment.' I therefore furtherA provide in eombinat1on with my improved oven a novel type of means` for rounding off the edges of the briquettesprior to subjecting them to the heat treatment.

These and such other objects of my invention' as may hereinafter appear will be-best understood from a description of an embodiment thereof such as is illustrated 1n the accompanying drawings. f In the drawings: Figure 1 is a plan view, with a portion shown in section, of a battery of ovens constructed in accordance with the teachings of my invention, the loading and unloading means not being shown.

Figure 2 is a side elevation thereof partially in section and showing a portion' of the y means. Figure 3 is a sectional view taken along the line 3-1-3 of Figure 2. l

Figure 3a is aperspective view of an individual casting, aplurality of which form the battery of ovens in myv preferred em-l bodiment.

Figure 4 isa partially diagrammatic plan view of the ovens and theloading means; y Figure 5 is aside elevation of theparts of my invention shown in Figure'4. l

Figure 6 is an end elevational view of the elevator for raising and lowering the discharging conveyor and the fuel container guide-way to positions oppositeeach respective oven. l

Figure 7 is a diagrammatic view illustrating the paths of travel ofthe products of combustion and the distillation products during the primary stage of the heat treatment through one oven.

Figure 8 is a diagrammatic View illustrating the paths 'of travel of the lproducts of combustion, products of distillation, and air during the second stage of the heat treat-l ment through one oven.

. Figure 9 is a detailed side elevationzothe; loading and unloading portion of my apparatus.

Figures 10 to 12 are diagrammatic. views illustrating the method of operating the loading conveyor to receiveja uniform charge of fuel thereon prior to discharging it into its respective f uel container, Figure 10 showing the conveyor discharging into a set of. pans adapted to be moved into an ovenv and hold the fuel during the baking operation, Figure 11 showing the conveyor receiving a continuous fuel charge at the completion of its loading operation in outside iositionijust prior to starting to move to inside position, and Figure 12showing'th conveyor receiving a second layer thereon while moving to inside position and not revolving.

Figure 13 diagrammatically illust-rates an` end and section of anzunrounded briquette.

Figure 14 diagrammatically illustrates any endl and section of :a briquette rounded-according to the teachings of my invention.

Figure 15 is a longitudinal sectional view. of the means I employ to round oli" the edges of the briquettes prior to discharging them, on to the loading conveyor.

Figure 16 is an end elevation of ratus shown in Figure 15.

Figures 17 and 18 are detailed side eleva-ir tions showing the action of the loadingfand unloading mechanism as applied to an indi-- vidual oven, Figure 17 showing the set of pans in full outside position at the end' of the dumping operation and the loading conveyor j ust starting to move outwardly over the pans,

to discharge the fuel briquettes carried there.-

by into 'the pans, dotted line representationsy also indicating the different positions the loading conveyorwill occupy in movingv outwardly overthe set of. pans to load, them;A

and Figure 18 showing the `pans moving to outside position and dumping their contents` on to the unloading conveyor while the loading conveyor, restrained from revolving,` is

being moved inwardly to receive a layer of fuel thereon.

Figuresl19 and 2O are side elevational views generally ysimilar to Figures 17 and 18, showing how my invention is applied'to a'batteryy of verticallydisposed'ovens, Figure 19 showing the fuel-loadingconveyor movingto inside position while not revolving to` receive Y a fuel charge thereon andthe discharging y. conveyor and the fuel container guide-way `moved to a position opposite the upper oven,

the discharging conveyor revolving to remove the baked fuel therefrom, andthe upper set of pans ymoving to inside and Fig. 2O showing the loading/ conveyor moving lto similar position but with the unloading conveyor and fuel containerorpan lguide-way moved to a position opposite the position ;u

second` highest oven` and theY fuel container i of baking ovens constructedin accordance with the principles of my invention. Suit-l able means are provided for uniformly heating the battery of ovens, which in my preferred embodiment comprise a series of fire boxes 32, eachbeingheated by the consumption ofamalgam, superfuel, coal, gas, oil or other suitable'fuel. rlhe fire boxes are each.. of thesame constructiom'two beingshown, forthe urpose ofcuniformly applying heat .indirect y to the surfaces of the ovens to produce therein substantially uniform temperatures-throughout their area.

Inl order that the working-fof my invention withv itsnecessary connections may be more readily understood, Ifwill first describe indetail theconstruction of the battery of ovens and then describe the heatconservation features thereof illustrating the flow' of vapors and gases inv connection with one baking chamber 3421s shown in Figures and 8, at,- the 'same'` time indicating in detail .theconnections totheebatteryfoffovens.` Although my'ba'tt'eryof baking ovens 30 may be vconstructed in any suitable manner,

in order that they `may bereadily madeand readily put vtogetherI preferably construct` the battery of baking ovens .from a plurality of castings 36' as-shown in Figure 3a. Each Y casting consists of' ank enclosed transverse passageway orf heat-ingschamber 38l `preferably providedwith means to produce a turbulentv iiowy of heatinggases therethrough'.4 In my preferred embodiment saidmeans `preferably comprises a series ofA baies 40- al.- ternately attached .to` opposite'sides ofv said' passageway to cause: the heating gasestot` follow acircuitous path on passage therethrough. I provide the legs 42, which preferably extend thefull length of the castingi 36 and depend from` eachv side thereof. Iy also provide similarlegs 43 extending upwardly fromthe upneri side of the casting 36. Theselegs are shown as provided with slots or grooves 44 to interfitwith beveled portions 45l on the leQ's 42 of the next adjacent'casting 361. To form an. individualV oven'30 a` plurality of these castings are laid end lto end in layers to form a longitudinal... baking oven'comprising t-he baking chambers 84betweenthe adjacent legs 42, said baking oven 30being adapted to receive, if desired, a removable4 fuel container or containers` 46. As stated, mv invention preferably includes f irming a battery of `horizontaljbaking-ovens 30 vertically disposed one above the other and to this end I'preferably i form layers ofsad castings` 36 on top of one i 'said battery of horizontal baking ovens 30 'the chambers 38 over vertically disposed one above the other. (See -Fig 3.) When the castings are assembled in this manner it is apparent that there will be a plurality of enclosed transverse heating passageways 38 extending underneath each oven to impart indirect heat thereto. As shown in Figure 3, hot products of combustion from the vfire box 32 are led to the heating chambers or passageways 38, through openings in one side thereof by means of a flue 52, which when a battery of ovens is employed is split into individual inlets 54 for each individual heating chamber 38A. The products of combustion after passing through the baffles v40, and in doing sogiving up a large proportion of their sensible heat, are led off through the outlets 56 from each individual heating chamberkto the common stack or flue 60.

While the castings may be constructed with openings in their opposite side walls to provide a single pass of heating gases therethrough, as shown in Figs. 3 and 3a, I preferably join said castingstogether to. provide zigzag passesfor the heating gases underneath each oven to more thoroughly impart the heat thereto. Thus, as shownin detail in Figures 1 and-'4, I preferably connect the fire box 32 with one end of a casting 36 having an open end 50 by means of a flue 52, which when a battery of ovens is employed is split into individual inlets 54 for eachl set of inter.- connecting heating chambers 38 as shown in Fig. 3. I preferably subject all the heating chambers in the battery to the `same amount of the connections for each set of zigzag passes for the superimposed ovens Y are preferably similar. Where a plurality of zigzag passes are formed through the heating lchambers 38 I preferably construct 'the set of heating chambers 38a opposite each individual fire box with the means to lead the products of combustion on the opposite side thereof to the next adjacent set of heating chambers 386, and so in my heat, and for that reason preferred embodiment I preferably construct the heating chambers 38erl with the openings 62 in one side thereofadapted to be in register. with the openings 64 in the adjacent set of intermediate heating' chambers 38?). Similarly the set of heating chambers 38o adjacent the common stack 60 are provided with the openends 66 which converge into the outlets 56 leading to the stack 60. The heating chambersv 380 are also provided with the openings 68 near the front ends thereof adapted to register with the openings 7 O the set of intermediate heating chambers 385. It isjthus apparent that in vmy preferred embodiment the heating gases willbe passed from the 'flue 52 through the inlets 54 into the individual heating chambers 38a, and

through the chambers 38, 38h and 38a vwill be further indicated by the arrows in Figs.

`1 and 4.

The fire boxes 32 are all preferably kept at the same temperature so that the whole oven will be subjected insofar as possible to the same amount of heat. It is thus obvious that when assembled my'i1nprovedbaking device comprises a battery of normally closed horizontal baking ovens 30, each comprising the baking chambers 34 formed between the cooperating legs 42 and 43 of adjacent castings 36, vertically disposed one labove the other, each oven having a fuel container'46 removable from one end thereoflfor charging and discharging purposes, and being vertically spaced from each other by the height of thev heating chambers 38 which provide horizontal transverse passageways for a uniform application of heat thereto, a common heat inlet passageway 52 discharging into said transverse horizontal passageways or heating chambers 38 through the individual heat inlets 54, and a common heat outlet passageway 60 leading from said horizontal passageways 38 through the individual outlets 56.

Inorder to reduce the temperature of the heating gases issuing from the fire boxes 32 tokeep the temperature in the heating cham` bers 38 at the desired level, I may, if desired, return part of the products of combustion from the flue or stack 60 beyond said oven to the lire box 32. In my preferred embodiment this pipe 72 leadiag from the stack60 to the fire box 32, said r turn pipe 72 having a blower or other means 7 4 therein to return lthe desired portion of the flue gases to the furnace, where such gases dilute Vor mix with the hot combustion gases to temper or cool them to the desired temperature. The speed of the blower 74 thus controls or varies the quantity of fiue gases thatmay be recirculatedin this manner, thereby permitting the employment means `comprises the returnv for this purpose of gases already heated te` someextent instead of using cold air or gases with consequent loss of available heat units dueto the fact that more fuel mustbe consumed iii-producing heating gases of the desired temperature when using the cold diluent gases than when heated gases are used.

As stated hitheiffto, my improved apparatus as a purifying agent.

The method of `said operation takmg place in the baking chambers 34 preferably successively during both the primary and the secondary stage of the heat treatment described therein in which different conditions preferably prevail, the apparatus herein disclosed being capable of carrying out in the distilling or baking chambers those changing conditions required in the operation of said method. Each fuel container 46 is filled with a series of carbonaceous fuel charges of a plastic nature which have been molded orotherwise shaped to the desired diameter and contour. Fuel containers so filled are inserted in the ovens preferably successively in amanner and by the apparatus to be explained in more detail l1ereinl after. Each oven 30 is heated during both stages of the operation by the circulation of heating gases from the fire boxes 32 through the heating chambers 38. During this operation the interior portions of the distilling chambers 34 are preferably heated to a tem` perature near but less than 600 F. for from one to two hours, -and preferably, as more fully explained in said application, in the presence of a limited amount of air. To insure that only a limited amount of air will be admitted to the distilling chambers 34 during this process I preferably provide in the pipes 7 5 connecting with the front ends of said chambers' the individual valves 7 6 which may be adj ustably set to admit the desired' amount of air to each distilling or baking 4chamber during the initial stage of. heat treatment.

All of the other passagesby which airv or oxygen could enter the chambers 34y are closed.

During this first stage baking operation moisture is removed from the coal and the lighter' constituents of the oil binder are likewise distilled or vaporized, preferably as described in said method app p lcation. x As also more fully explained in the method application, in order to avoid danger of vapor fires and explosions, the initial stage of heat f treatment is continued until no explosion will occur on the admission of more alr, which in the baking of amalgam usually takes from one to two hours. the oil distilled from such amalgams are valuable light products of a condensible nature, such as gasoline, which products are recovered inthe operation of my improved appa-y ratus by being permitted to pass through the line 7 8 controlled by the two-way vvalver80 to the line 7 9 leading to the condenser 82 as vshown diagrammaticall in one oven in Fig;

ure 7. The lighter en s ofthe condensible products passing through the condenser are condensed by the cooling action of water passing around the condenser pipes 84, and such condensed products may be continuously withdrawn from the condensers for subse- The lighter constituents of quent use. Certain uncondensed products as well as fixed gases escape from'the condensers 82'and I preferably pass such gases and products through the lines 86 to the fire boxes 32 where they may be consumed and assist in generating the heat necessary for carrying on the process. It is thus apparent that by manipulating the two-way valve to openy up the line 7 9 during the initial stage of the heat treatment; the condenser 82 and return pipe 86 may be intermittently connectible to each individual distilling chamber 34 to permit the recovery of volatiles and the utillzation of the fuel values in heretofore lost products;

As stated hitherto, the presence of air or According to the teachings of my 'method i application, when this preliminary or initial heat treatment of the amalgamvmasses or yother material being baked has continued a sufficient time so that no vapor res or explosions will take place on the admission of more air and to recover an optimum quantity of oil, the atmosphere of the heating chamf bers 34 is then changed and the partially heated charges subjected to their final stage treatment. his second stage treatment preferably takes placein the presence of excess air and I therefore provide means to admit air to said distilling or baking chambers 34, which in my preferred embodiment comprises the airinletfpipe 90 through 'which air is admitted, if desired, under pressure. For purposes ofheat conservation I preferably also provide means to 'pass said a1r in counf tercurrent heat interchange with thewaste products of combustion being led `from the oven to the stack to preheat said air. In my preferred embodiment said means comprises a heat interchanger, preferably consisting of the annular sleeve 92 surroundin the flue discharge pipe or stack 60. This s eeve communicates withl the air inlet pipe 90 and with shutting off the condenser and'placing the' baking chambers in communication lwith the heat interchanger so as to receive preheated air therefrom. A blower or other means may be employed tovforce the air into the baking chambers 34 if desired. As stated hitherto all the ovens are preferably heated to a uniform heat but, articularly if bituminous coal is being distilled, the temperature during the second stage of thetreatment may rise due to the exothermic reaction between the carbonaceous and/or oilfractions and oxygen. This reaction is controlled 'by limduced is commingled with lar itng the amount of air admitted to the ovens or otherwise referably so that the temperature of the el will no t rise so high that the ca i'bonaceous content of the fuel will show incandescence.

There is little condensible vapor, particularl if anthracite `is, employed, produced during the second sta e of the operation and because ofthe fact t at what vapor vis proof air, etc., the condensation o such vapor durin the secondstage:A isusually no t warrante Consequently t eA gases removed during such stage pass through the lines 7 5 to the re box/32 of the lfurnace. To permit of individual' operation of the respective baking chambers84, dampers 100 are lacedin the lines 75. The products conduct i through these lines consist of fixed` gases, somev distilled gases and 'heated air which has purly been admitted, as explained, to the akin chambers. 34. Of theseproducts the heate air helps support combustion in the fire box while the uncondensed gases provide a fuel to assist in carryin on the rocess.L AsA stated in said co-pen ing app icatioi the second stage ofthe operation is continue 'each other.

. sel

Although I have described a battery of baking ovens itis obvious that insofaras certainfeatures of heat conservation, etc. are concerned, these' features are applicable to a' single oven as shown diagrammatically in Figures 7 and 8. "It is also apparent that my improved oven or battery of ovens, while prlmarily adaptedfor distillingfuel 'amalgam in two stages according to the teachingsvv of my method application, maybe employed toheat lor bake othermaterials such as coal, etc.

.Asststed gam accordingto the continuous ,amalgamation" process of my applicationv Serial No. 204,069, the,amalgain is formed continuously,

quantities proper manipulation -of thethe apparatus. As shownhitherto, inmiinufacturing amaland led through the extruding machines and preferably lthrough the l rounding-off ma-l chines disclosed in thispresent application continuously, but in order that the prop-A er-baking of the amalgam may takeplace with optlmum conditions of safety and for the production of the bet-tertype of vamalgam briquettes, it is apparent that a twostage baking treatment, the second in the presence of excess air, cannot take place continuously but must take p'lace intermittently in two well defined separated stages, and further features of my invention therefore include an improved method of receiving material continuously and uniformly charging and discharging successively a battery or' ovens.i I believe .ly am first to provide a method of changing a continuous feed into an intermittent feed to provide in. each oven 30 of the-series a substantially uniform charge of material to be heated. My invention there-` foreincludes aprocess of intermittently producing uniformly baked charges of prepared solid fuel from a battery of vertically-disposed baking ovens 30, each having a fuel container 46 removable from one end thereof and all subject to substantial-ly uniform heat, while continuously feeding a uniform layer` of material on to an endless conveyor overlapping' one end of said battery, successively removing the fuel container 46 from the baking `chamber 34 of eacl individual oven 30 to a position underneath saidy conveyor, dumping the contents of said conveyor thereon and, successively returning the fuel container 46 to itsrespective oven 30 Y. at such substantially uniform periods of time that each oven will receive asubstantially equal fuel charge from the conveyor. Means are also provided for dumping the baked contents of each fuel container 46 while attain ing a position outside of said oven underneath the conveyor to receive a' freshfuel charge. I therefore provide means to successively remove and return ythe fuel con. tainers from and to each respective oven at the end of its respectivebaking period, means to dump thecontentsf'o'f each respective con,- tainer while moving to a position outside of its respective oven, and means to continuously receive fuel and intermittently uniformly load it on to'each respective container when it has been emptied ofits previous charge and is in a loading position outside `of its respective oven.v Itis thus apparent that each fuel container from each oven will be successively discharged and filled at regular successive time intervals, thereby permitting a continuous feel of fuel to the loading means hereinafter to be described. v 4 Although any suitable ty e of 'fuel container 46 may be employed, -preferably employ a plurality of 4pans 102 arranged transversely between the V-shaped rods 104,'longitudinally slidable to positions inside and specifically described heretofore.V I provide igesssor outside of the respective-bakingchambers34? of the ovens 30. Asshownlin Figuresrl and.,

18, my invention may be employed for chargf ing and discharging a singlle oven but it. is.

means for moving the pans 102'to positions inside and outside of the ovens 30 as; eX- plained hitherto and shown in detail in'Figure 3.- The pans 102 are mounted onthelongitudinally-extending V-shaped rods'104 which are supported on the pulleys 106, provided with cooperating V-sliaped grooves 108l onV the inside of each disti ling chamber. zThe tending through bearings in the sides of the .and 118 are provided.,

castings 36, which shafts on'the'ir outer ends carry sprocket drive wheels 112. I also provide means for supporting said fuell containers when moved to positions outside of said oven, said means comprising a line of V- shaped grooves 108 on supporting pulleys 106 similar to those employed inside of said oven. The pulleys 106 outside of' the oven are mounted in alignment, the same as those: in the oven, and form an imaginary guideway 114. It is apparent that when the fuel containers are moved to 4positions outside off the ovens the V-shaped pan-supporting rods 104 will ride on the guide-way 114 exteriorly of the ovens in similar fashion as it rides on the imaginary guide-way- 115 formed by the upper rsurfaces of the V-sh-aped pulleys 106 within the baking chamber ofeach res ective oven 30. The pulley shafts 110'for t e pul, leys 106 formin the guide-way 114 areprovided with drivmg sprockets 112 the same as those mounted within the baking chambers.`

-To move the fue] containers/16 to positions inside and outside the baking chambersl` I provide separate drive chains 116 adapted to mesh with the sprockets 112 permanently attached adjacent the sides of the respective baking chambers of the ovens for moving the :fuel containers while inside of each individual chamber 34.` and chain 118 .outside of each oven for moving saidfuel containers. when outside of'said oven. The'chainspll if desired, with 'tight` ener pulleys 120 and .alsowith tighteners` 122. The drive chains 116 and 118 may be driven in ,any suitable manner such as bythe drive chains 124 driven respectively by mo: tors 126. It is obvious-that if desired all'. of the drive chains 116 for moving the fuel containers within the ovens may be driven by one motor 126 through a plurality vof drive chains 124 (see Fig. 5). I also provider-aheated'matcrial discharge receptacle for tak- 1 ing away the dumped contents of said pans which' in my preferred embodiment com-y prisesan endless discharging revolving con-A veyor" 128. which@ revolves as desired. underneath the outside position. of said. pans-102. Said' conveyor-128 discharges into .the chute 130 and is' revolved fordischarging purposes atV the desired timesbymeans of the drive chains 132.suitablyoperatedby the motors 134. I also-provide means vto discharge the contents of the pansfl02 on to the discharg` ingconveyor128 while the pans are riding on the rods'104' to positions outside of their respectiveovens, saidnieans preferably comprising'the tripping lever 136 adapted to abut the cams 138 on each respectivepan 102 to tipthem up to dump Vthem as shown more particularlyinflfggres 9 and 20, said trippy,lping-lever A136 bemgmanually or automati- I y cally throwable .intoa or out of tripping 'posi` pulleys 106 are mounted on shafts 110 ex-A .as supported for travel vto and fro from a positionabove the'oven 30 toa position above the outside positions of the'pans 102. The conveyor is. providedgat intervals with the drive shafts`l44, Whichrrturn are supported in bearings 146in:thebrackets 148 laterally depending` from. the longitudinal Vlshaped guider-rails 150 adaptedto register in cooperatingVshaped grooves 154` onthe pulle` s 156,- which in tur-n are provided with sha s 158 -ext ending.to.thedrive sprockets 160 exterior thereofi. ,The pulleys 1v56'are-continu`- ously drivenby the chain-162 registering. in the sprockets 1.60, which .also arel provided wit-h suitable lidlers 164l for slack therein and; which.` may be suitably driven bythe motor 166fthrough the medium of" the drive chain 1.68.'. The ulleys15'6 are in longitudinal. alignment-and) therefore the upper surfaces of( theV-shapedgrooves 154- formf an imaginary guide-.way twice the length of. an ovenor. conveyor in which the guidel rails=150 supporting. the conveyor are adapted 4t'o-move. I: also provide meanstd automatically reverse the directions of travel of the'convey0rf142 so thatv it maybe continuousl moved` to positions above the inside an outside positions ofthe fuel containers or pans. In` my preferred embodi-v -150 may actuate it to reverse. the motor 166 to reverse the direction, of rotation ofthe taking; up the iso chain l162 to move the guide rails 150 inward,

and the switch 172 being attached similar fashion to `abut the inner end of one of the guide rails 1.50 to reverse the direction of travel of the conveyor when said conveyor attains its innermost position immediately `above the ovens 30, said switches 170 and 172 being preferably spring controlled to be automatically moved back to a position to again contact the end of' one of the rods 150.

As will be more apparent from the description of the operation of theloading conveyor, it is necessary to revolve'said loading conveyor 142 when moving to a position above the outside position of the'pans 102 in order' to dum the contents thereof on to the pans 102y an to prevent the rotation of said con;

veyor .142 while moving to inside position to build up the desired charge thereon. To'this lend I provide the sprockets 174 on the ends Y of the drive'shafts 144 and train thereover the chain 176. A pivoted pawl 178 so situated as to enmesh with the chain 176 when the conveyor 142 is moving to outside position to cause revolution thereof and to slide over said chain without engaging it so'as to not to permit said cha-in and attached conveyor` to Y revolve-Whenl moving to inside position is i the fuel charges may not be dropped to any 128 vertically up and down' preferably simulgreat distance thereby causing distortion thereof, andfor purposes lof heat conservation, to move the fuel container imaginary l guide-way 114 and the discharging conveyor taneously, -so that the imaginary guide-Way 1,14 may take positions immediately opposite the imaginary guide-Wayflll within the'baking chamber of each respective oven and the' fuel containers or pans may be moved directly outwards from one guide-'way to the other with the discharging conveyor immediately below the guide-way 114. To this end I provide the elevator 180 which has the latform 182 vertically movable up and down y means of the hydraulic plungers 184. The plungers 184 are preferablyv suitably con,- nect'ed together so as to be simultaneously operated by the same hydraulic means 186 to,

equalize the -pressurein each plungerl andI to uniformly and horizontally lift the platform 182. The V-shaped supporting pulleys 104 formin the imaginary guide-way 114 and the shall-'ts for moving and supporting the discharging conveyor are suitably mounted in the girders or other supporting means 188 mounted on each side of the elevator platform.

As stated`hitherto,'my invention is par- ."Figure 14 ticularly adapted for vbaking amalgam `briquettes.

truded through the ordinary extruding machine are normally cylindrical asshown in Figure 13, and square or rectangular in longitudinal section. I have-discovered, particularly if the briquettes are not thoroughly carbonized throughout, thatby merely'having the outer surface hardened the square edges of the briquettes are apt to break off leaving a soft 'inner portion which is apt to dust and crumble in use, and I have found thatthe briquettes can be made more self-sustaining and non-dusting and can be more easily handled if the edges thereof are rounded 0H in yAmalgam briquettes 19() when exmanufacture, as in the briquette shown' in at 192. To this end I provide'as shown in Figures l5 and 16, preferably in combination with `the rest of my apparatus,` means to round off the -edges of said briqucttes before delivery to said loading ieans. aid means for rounding off the surfaces of the lbriquettes comprises a table 194having a pluralityI of channels 196 slightly larger than the briquettes, extending longitudinally across the upper surface thereofand preferably downwardly inclined, having irregular Wavy surfaces formed by the-protuberanccs 198 therein. In order to shake the table to round ofil the edges of the briquettes l provide means to vibrate said table laterally preferably in a horizontal plane such as the eccentric drive 2,00.y c The operation of my invention is apparent from the above description of my improved apparatus'. After the amalgaml masses have been formed in the manner described in mylprior patents above referredto they are continuously molded into forms of predetermined contour preferably'in the shape of cylindrical briquettes asshown inv Figure 13 by passing through anextruding machine. In

order tok round ott/the edges ofthe briquettes to make them lmore easy tol handle andless dusting in use, particularly if the briquettes are not uniformly hardened throughout in accordance with the teachings of my method application Serial No. 234,261, I preferably round ofi' the edges of said briquettes fromthe cylinders shown at 190to the general elliptical shape shown in Figure 14. by passing them through the vibrating table v194 for other means employed for this purpose, from whichl v they 'are continuously discharged on to the loading conveyor 142.

As stated hitherto I preferably subj ect successive charges of brique'ttesto heat treatments of similar y time-controlled duration" and I therefore preferably divide the number of ovens in they battery, less one needed for loading and unloading` purposes,into the time necessary to subject the briquettes to the desired two-stage heat treatment, and I arrange to continuously feed the briquettes on to the loading conveyor and to intermitin the baking 'cham containers or pans and introduce such containers intotheir respective ovens 'at intervals determined bythe calculation above indicat-` ed. I therefore preferably first load any oven, say the upper one, and then successively discharge the other'ovens in cycles of uniform baking periods. As shown in Figures 9, 10 and 17 the elevator'180 is first raised' to a position so that-the guide-wa 114 will be substantially op osite the -guil e-way 115 er of the upper oven 30, the discharging conveyor being simultaneous,- ly raised therewith toga position immediately below it. on to move the upper fuel container 46, comprisingra set of pans 102,' to'a position outside the upper oven 30, the guide rails 104 moving from the. imagina-ry .guide-way 115 l inside the oven to the imaginary guide-way 1 14 outside the oven, the lever 140 having sition as shown in 'Figures 12, 18 and 20. It

is apparent that whenv the pans 102 have attained their outside position theyy have completely dumped the contents thereof on to the discharging conveyor 128 and the load-'i ing conveyor will have attained its innermost y position, the position shown'in Flgure 17 ori,

as shown by dotted lines .in .Fi uresll, 12

and 18. After the contents offt e pans `102` have ,been completely dumped on to the' disy the chute 130, or,

charging conveyor 128 the motor 134 for discharging the same may be switched on thereby permitting said discharging conveyor to revolve and discharge its contents through conveyor may be operated as the ans 102 move to their outside position. pansf102 have attained their outside position as shown in Figures 10 and 17 the apparatus is so fset up 4that the loading conveyor will start to move from inside to outside position and the pawl 178 will then engage the cha-in.

176 to cause revolution of the conveyor 142. It is apparent that the conveyor 142 will revolve to discharge the'contents thereof uniformly into the pans 102, while moving to itsl outside position. Auniforrn charge of fuel is thus distributed therefrom into eachrespective pan, as more particularlyshown by dotted lines in Figures 10 and 17 As the distance from said-conveyor 142 to saidpans 102 is so small it will not distort the green briquettes to any appreciable degree. Vhen the loading conveyor 142 has attained-its outside position it is apparent that it will have completely discharged its contents uniformly `'switch 170 to cause the The'motors 126 are then turnedl riquettes been adjusted so that the' tripping lever 136, will abut the cams 138 on each respective pan u is apparent,

ynipulated'so t p "114 thereof 'will bev` op moved to outermost if desired, the discharging:

lthe next highest oven en the uniform layer of green fuel in Figure 11, and that it will have tripped the f i `motor 166'toreverse, thereby changing the direction of travel of the chain162 so as to move the conveyor 142 from outside to inside position. j i

After the pans 102 have been uniformly filled lwith briquettes, it is apparent;y that the i.

motors 126 for driving the outsidev andinrespectively, v drive the chains in a direction the pans to inside position.

takes place at a quicker rate than vthefmoveplaineddater. l 142 is moving to particularly shown in Figure V12,-the' fuel are continuously i discharging side drive chains 116 and 118 for the pans may be `so switched on as to roperto move 1 ,i he moving of the pans 102 to inside position preferably` thereonto form a second layer of fuel therei on and it is apparent that Vwhen .the lfuel conveyor has attained its inside position,;as f

shown in Figure 10, it will have a double layer of briquettes or other fuel thereon. 'It l,

that two distinct layers l however,

may not be formed as the upper layer may."

vsift down between the lower ylayer,'or ifj timing conditions are not exactlypright` two full layers maynot, be formed.

ing its inside positionv yan pans `102have, lbeen returned to the upperv oven. 30, the h ldraulic elevator is then maat thel ima guide-way inside t proper rotation of the and 118 to completely move said pans from n to the elevator 180,y

While the loadingv conve or 142 is attaiiii dy after the upper '11W ginary guide-way i osite the Imaginary e next highest oven, f 30. The removable container 46 or pans 102 from said nexthighest oven 30 are ,thenposition by means of motors 126 drivingre-J vspectively,theinsideand outside chainsy 116 and to simultaneously'dump` the contents discharging conveyor 5128, The elevator 180 1s then moved to aposition opposite the upper ovenl and immediatelybelow the loading conveyor 142before the loading conveyor 142 at- -tains'its full inside position. When the loadn ing conveyor, reaches its full 'inside position 1t trips `the switch 172I to cause areversal of the motor 166 andconsequent movement of the conveyor `teoutside Aposition to dump the contents thereof into the pans 102 from the on tothe loading lconveyor I do not mean to thereof, in a? mannerexplained,^on to the fue las

yimply that the threerl'ayers are necessarily exactly superimposed one above .the other,

yed. ontheconveyor continuously during three .passes thereof beneath the discharge outlet fromqthe briquetting machine or from the rounding-o1! machine.. In practice the bri-v quettes f he .about and. through the loaded-containers. will y tion offsa'id'elevator result if conditions are so controlled-"as to produce za. charge .of a thickness correspond,- ing to that 'of Ytwo layers of the b ri nettes. The hydraulic elevator 18,0 l is pre erably raised its uppermost position for several reasons,.among othersto obviate a fall of `any substantial'distance for the green fuel Afrom the loadingiconveyor 142v into the respective fuel` [pans 102 and therebyto prevent distorf tion of the green fuel. rl-he unloading conveyor isrased and o .n y e therewithf'so that the heat from the heated briquettes temporarily lying thereon immediately below the pans 102'y will prevent them from appreciably cooling oil'l beforebeingA reinsertedE in .their respective ovens 30. By simultaneously moving the discharging conveyor 128 'wi-th the imaginary guide-way `114 any great drop of baked briquettesy in .their discharge fromthe pans 102 with resulti dustinglor distortion thereof is prevente 'I "he discharging conveyor is, however, always maintained in positionl for discharge to thje chute 130. The operation is continued in the manner hereinbefore described,load ing successively each 'respective oven intimecontrolled eriods'. Y The speed of movement of the loading conveyor from outside-to inside position is so regulated that the time required for such movement will lalways exceedl the time required to move the elevator y 180'f-rom uppermost position immediately b'eneath said conveyor 142 to return the fuel container 46 or pans 102].to the next tothe lowermost oven, then to a' yposition opposite the lowermost .oven to recelvethe fuel container therefrom while dumping the contents thereof on tol fsaid discharging conveyor 128 yand then raising said` .tuel container from ythe lowermost oven tothe uppermost posiimmediately underneath said loading conveyor` 142 before said loading conveyor l14:2 starts tol move to outside position to .discharge its contents into said uel container from the lowermost oven. It

thus apparent that I am` enabled to successlvely load and unload at successive' timeeontrolled intervalsfuel charges to a battery second' fandy thirdy layers may actuallyxsift 4down between thebriquettes of vthejfirst 'layer `so that substantially ay `single lowered lsimultaneously .of vertically/disposed baking ovens.A Al'.- t-hough the loading and unloadin featuresof. my invention areV particularly `l esigned for use inmbaking" ainaflgam= briquet-tes, it is `obvioustha-t theyfnay beemployed for `loadinga battery of `ovens for heat treating `any type of material, onthat thel lloading. conveyor with proper speed regulation may he em'- ployed for changing a continuous feedintofa'nfintermittent-feed for a single oyen, as more particularly shown". in Figures 105 112, 17 and 18,` inj' which ,case .of cou-rse,` the .ne. cessity for .thefelevator and vertical? movement .of .the sfide-way .114 and' disahargng vconveyor 128"may be dispensed-with.

As stated hitherto the heat conservation features .of myinvention vare ,also particularly `adapted for artwo-stage treatmentf,ofl tufelj, preferably amalgamybut I believe .that certain features 'thereof areg broadly new any e 4type of oven aswel'lfas certain' loadingand unloading features of my invention` and that they are `equally.applicable either to a single ovenk or to abattery of ovens adapted function successively to giveuniiormfcharges of fuelv successive uniform: time-controlled: heat'k treatments...

It is understoody that my invention isnot limited tol the specific embodiments shownV and that various deviations may bemade therefrom without y* and scope of myiappendedielaims;

' What I `clainris:

1.- Ink combination, a chamber for receivingv materiali containing. a volatile content to heated.a.frebox, means for leading. productsv of combustionfrom said fireb0xthroughpas- `sages adjacent said chamber for indirectly heating .the same to yremove volatiles from vsuch` material", meansl independent of said departing` from the spirit- "lof chamber for returning without passagev through the chamber controlled amounts of said products-.of `combustion issuing. fromsaid passages and mixing them with products of combustion being introduced thereto and means for introducingV to the fire box a portion ofthe volatilesy removed for. consumption therein to generate gasesto mix with the products yofl combustion returned to the fire box. o V

2. In combination, a chamber f orrec'eiving materigal'to be heated,a rehox hav-ing. `a flue for the products of combustion passing in proximity lto said .chamber for" indirectly heatingthe same` means for* returning part ofthe products of combustion from said flue v beyond said vchamber to the Firebox to; reduce the temperature thereof, means to admit air to said chamber, means to pass said air in counterc'urrent heat interchange' with the waste-products of `combustion in said flue bei yond said ychamber to prehe/at said air, and means leading directly lfrom saidrlch'amber to said irebox to lead air and' volatiles from said chamber connectiblevto said oven simultaneously withthe opening of said air inlet means. H

3. In combination, achamber for receiving material to be heated, a firebox having a flue for the products of combustion 'passing inv proximity to said. chamber for indirectly heating the same, means for returning Apart of the products of combustion from said flueA beyondsai'd chamber'to the irebox to reduce the temperature thereof, means to admit air to said chamber, means to passsaid air win countercurrent heat 'interchanges-v with t'ne waste products of combustion insaid flue beyond said chamber to` preheat; said air,. a condenser, a valve operable to connect or d1sconnect the condenserwith-the chamber, and means to lead non-condensed volatiles and gases from said condenser to said firebox, and

means leading directly from said chamber to said firebox to lead air and volatiles from said chamber connectible to said chamber to said fire box. l a

4. In combination. a chamber for rece1v1n'g material to be heated, a Iirebox having a flue for the products of combustion passing 1n proximity to said chamber forV indirectly heating the same, a vapor outlet for said chamber, a condenser connected to said outlet, means to lead non-condensed volatiles and gases from said condenser to said firebox,

means for disconnecting said condenser from said outlet, and means for introducing air to said chamber through said outlet when the condenser is disconnected therefrom.

5. In combination, a chamber for receiving material to be heated, means f or indirectly heating said chamber, a lcondenser connectible to and disconnectible from said chamber, means to lead controlled amounts of air to said chamber while the condenser is connected thereto, means for introducing a larger amount of air to said chamber when the condenser is disconnected therefrom, and means zontally-disposed elongated baking ovens vertically disposed one above the other and a plurality of enclosed transverse passage- Ways extending underneath each oven to impart indirect heat thereto, certain of said castings having closed ends and communicating with adjacent castings to form a plural- [underneath each oven.

ity of zigzag passes f 7. A baking device comprisin 'a plurality of castings each having an enc osed transverse passageway, `legs substantially `the length of the casting dependingffrom each side thereof and slotted ortions carried on the upper side thereof immediately above each le said castings being disposede-nd to end in ayers-,with the legs ofthe `upper layer's fitting into the slots'in the lower layers, ,4 to vform va. battery of horizontally-,disposed elongated `baking ovens verticallydisposed one above the other anda plurality of enclosed transverse passageways extending Y under-L neath each ovento impart indirect heat thereto.

48. A casting for use in making an oven comprising walls defining anenclosed transverse passageway, bafllesdependingfrom opposed walls into said' passageway, legs substantially the length of thejcasting dependorv the heating gasesY l ing from each side thereof, slotted portions"` leg, and openings communicating withsaid s passageway.

10. A casting forl use in making an oven.,y

use v1n making an oven comprising walls defining an enclosedtransverse passageway having baffles therein, legs substantially the length r of the casting extending from opposite sides thereof, the extremities of one pair of legsr being slotted and tbe extremities ofthe other pair being shaped to fit into such" slotted portions of an adjacent casting when assembledinto an oven structure. t i l 11. A casting for use in making `an oven comprising walls defining an enclosed transverse passageway,` legs a substantially the length of the casting `extending from opposite (sides thereof, the extremities of'one pair of legs-being slotted and the extremities of the other pair bein shaped to fit into such slotted rportions o an adjacent casting when assembled into an oven structure. ,t

12. A baking fdevice comprising a pluralit` of castings adapted to b e superimposed, eac casting having ay passageway for .heating gases. and a -heating`chamber, said passagelocs` ways and heatingchambers being disposed in axial alignmentfwith adjacent superimposedrowsof castings`,means for admitting heating gases to each of said passageways, means for supporting material to be treated in said chambers. a furnace, and means independent of said chambers `for returning a portion of the products of combustion passing gases to said ing through said passageways to said furnace wlthout passage through the chambers.

13. A. baking oven comprising a series of castings arranged one u on the other longitudinal rows, each casting having a heating chamber therein and a fuel'passageway surrounding said chamber, the heating chambers 'and passageways of the castings ofk one row being in axial alignment with the heatin chambers and passa' ewaysof the castings o i the adjacent rowan means for feeding heatpassagewa s, com rising a furnace, and means indepen ent of t e chambers for returning-a portion of the gases after assage through said passageways to said burnace without passage through the cham- CIS.

14. In combination, a chamber for receiv` ing material to be heated, a firebox having a u 4in proximity 'to said chamber for in irectly e for the products of combustion assing heating the same, means to admit air to said chamber, av condenser communicatin with said chamber, means for leadin uncon ensed gases fromsaid condenser to sald firebox, and

18. In combination, a chamber for receiving material to be heated, a irebox havmg a flue for the products of combustion assmg in proximity to said chamber for in 'rectly December, 1927. Y

` WALTER ETRENT.

' a direct communication between said chamber and saidtirebox for passing air and volatiles from the former to the latter.

15. In combination, a chamber for receiving material to be heated, a firebox having a flue for the products of combustion assmg i in proximity to said chamber for in 'rectly heating the same, means for returning part of the products of combustion from sa1d flue beyond said chamber tothe rebox to reduce Vthe temperature thereof, means to admit air to said chamber, acondenser communicating with said chamber, means for passingvuncondensed gases-from said condenser to said frebox, and means rfor passln lair and vola- *tiles from said chamber to said rebox. l

16. In combination, achamber for receivin material to be heated, a rebox having a ue for the products of combustion 4assing in proximity to said chamber for in irectly heating the same, means forreturning part of the products of combustion from said flue y beyond said chamber to the irebox to reduce to said chamber, and a directcommunication ybetween said chamber and said frebo'x for passing air and volatiles from the former to the latter. Y

17. In combination a chamber forreceiving material to be heated, a {irebox havin a flue for the products of .combustion assing in proximity to said chamber for in 'rectly heating the same, a vapor 4outlet for .said chamber, a condenser connected tol said outlet, means for disconnecting said condenser from said outlet,'means for introducing air to said chamber through said outlet when the condenser is disconnected therefrom, and

means for passinrair andlvolatiles from said chamber to said ebox.

"i the temperature thereof, means'to admit air f y 

